Fan with ring and method of producing the same

ABSTRACT

To provide a method of forming a fan with ring in one piece from a single metal plate and to provide the fan formed using the method, the metal plate is plastically worked into a shallow pan shape so as to form a cylindrical ring portion  1  on the periphery. A boss portion  2  is then formed at the center of the bottom portion of the pan shape, cutting all portions, except for part of the front end edge along the radius of each of blade portions  3  and part of the edge of the ring portion  1  for use as connection portions  4  so that the plurality of radial blade portions  3  are slit and formed.

TECHNICAL FIELD

The present invention relates to a fan with ring used as anairflow-generating fan for an automobile radiator and so on and to amethod for manufacturing the same.

BACKGROUND ART

A fan installed at the back or front side of an automobile radiator,etc. is known front ends of whose radial blade portions are joined inone piece by a cylindrical ring. FIG. 8 illustrates an example of such afan or a resin fan 12 in which a number of blade portions 3 are arrangedradially on the outer perimeter of a boss portion 2, in which the frontend edges of the blade portions 3 along the radius are connected to theinner surface of a bellmouth-shaped ring portion 1 in one piece and inwhich the blade portions 3, the boss portion 2 and the ring portion 1are integrally molded from synthetic resin. The blade portions 3 have ashape twisted at a given angle relative to the plane in FIG. 8A.

A center hole 7 is provided at the center of the boss portion 2, and amotor rotary shaft is inserted into and fixed in the center hole 7.

A conventional fan with ring made of resin are manufactured by injectionmolding and has the drawback that the overall weight becomes heavierbecause of the need to make the blade portions 3, the boss portion 2 andso on as thick as or thicker than a given thickness for convenience ofmolding and in respect of strength.

It has also been difficult heretofore to ensure exact uniformity inthickness of all the blade portions 3, thus resulting in quality-relatedproblems such as slight fan imbalance during rotation.

Further, there has been a possibility of resin shrinkage, deformationand other problems associated with molding during injection molding.

In order to solve the aforementioned problems, it is an object of thepresent invention to form in one piece a fan with ring by press-moldinga single uniform metal plate. It is another object of the presentinvention to provide a manufacturing method thereof that ensures ease ofmanufacture and high quality.

DISCLOSURE OF THE INVENTION

The invention as defined in a first aspect of the invention provides afan with ring comprising:

a cylindrical ring portion (1); and

a plurality of blade portions (3) located within the ring portion (1)and projected radially from a boss portion (2) at the center, wherein

the fan with ring comprises connection portions (4) constituted byconnecting in one piece part of the front end edge of each of the bladeportions (3) with part of the edge of the ring portion (1), and wherein

the blade portions (3), the ring portion (1) and the boss portion (2)are molded in one piece from a press-molded form of a single metalplate.

The invention as defined in a second aspect of the invention providesthe fan with ring according to the first aspect of the invention,wherein

the blade surface of each of the blade portions (3) has a sloped planetwisted relative to a plane of the boss portion (2), and wherein

the connection portions (4) at the front ends of the blade portions (3)are formed in one piece such that sloped concave portions (16), that arediagonally depressed, with the edges included in the ring portion, areflush with the sloped planes.

The invention as defined in a third aspect of the invention provides amethod of manufacturing a fan with ring comprising the steps of:

plastically working a metal plate into a shallow pan shape so as to forma cylindrical ring portion (1) on the periphery; and

forming a boss portion (2) at the center of the bottom portion of thepan shape, slitting and forming blade portions (3) radially from theboss portion (2), and cutting all portions except for part of the frontend edge along the radius of each of the blade portions (3) and part ofthe edge of the ring portion (1) for use as the connection portions (4).

The invention as defined in a fourth aspect of the invention providesthe method of manufacturing a fan with ring according to the thirdaspect of the invention, comprising, after the step of plasticallyworking a metal plate into a shallow pan shape, the steps of:

forming the boss portion (2) at the center of the bottom portion of thepan shape, and cutting at least the contours of both edges along thewidth of each of the blade portions (3) in order to form the pluralityof blade portions (3) radially from the boss portion (2); and then

cutting all portions, except for part of the front end edge along theradius of each of the blade portions (3) and part of the edge of thering portion (1) for use as the connection portions (4), and twistingeach of the blade portions (3) relative to the boss portion (2) forplastic working.

The invention as defined in a fifth aspect of the invention provides themethod of manufacturing a fan with ring according to the third aspect ofthe invention, comprising, after the step of plastically working a metalplate into a shallow pan shape, the steps of:

forming the boss portion (2) at the center of the bottom portion of thepan shape, cutting all the contours of the plurality of blade portions(3) except for both edges along the width and part of the front endportion of each of the blade portions (3) in order to form the pluralityof blade portions (3) radially from the boss portion (2), and formingenlarged hole portions (13) for crack prevention at the contour edges ofthe front end portions; and

then

cutting all portions, except for part of the front end edge along theradius of each of the blade portions (3) and part of the edge of thering portion (1) for use as the connection portions (4), and twistingeach of the blade portions (3) relative to the boss portion (2) forplastic working.

The invention as defined in a sixth aspect of the invention provides amethod of manufacturing a fan with ring comprising the steps of:

plastically working a metal plate into a shallow pan shape so as to forma cylindrical ring portion (1) on the periphery;

forming a plurality of sloped concave portions (16) for formation ofblade portion sloped surfaces on the outer side of the pan bottom, thesloped concave portions (16) being evenly spaced apart from one anotheralong the circumference and being depressed radially from the center ofthe pan bottom, with the edges of the sloped concave portions (16)included in the peripheries of the pan shape; and

forming the boss portion (2) at the center of the bottom portion of thepan shape, slitting and forming the blade portions (3) radially from theboss portion (2) such that the sloped concave portions (16) constitutepart of the respective blade portions, and cutting all portions, exceptfor the boundary between at least the front edge portion along theradius of each of the blade portions (3) and the ring portion (1) foruse as the connection portion, such that the boundary constitutes thesloped concave portion (16) in itself.

The invention as defined in a seventh aspect of the invention providesthe method of manufacturing a fan with ring according to any of thethird to the sixth aspects of the invention, wherein the enlarged holeportions (13) for crack prevention are formed in advance on both ends ofthe connection portions (4).

The invention as defined in an eighth aspect of the invention providesthe method of manufacturing a fan with ring according to any of thethird to the seventh aspects of the invention, comprising, after thestep of plastically working a metal plate into a shallow pan shape, thestep of:

forming notches (15) in advance from the inside of the pan bottom at thepositions of the front end edges of the blade portions (3) at theboundary between the bottom edge of the pan and the periphery of thering portion (1) of the pan, the notches (15) not stretching to theouter surface of the metal plate.

The fan with ring and its manufacturing method of the present inventionare configured as described above and produces the effect describedbelow.

The fan with ring of the present invention has connection portions 4constituted by integrally connecting part of the front end edges of theblade portions 3 with the edge of the ring portion 1, with the bladeportions 3, the ring portion 1 and the boss portion 2 formed in onepiece from a press-molded form of a single metal plate, thus ensuringease of manufacture and uniform thickness and providing a well-balancedand high-performance fan.

It is also possible to use a relatively thin metal plate, thus providinga fan that is lightweight as a whole.

In the above configuration, the blade portions 3 have sloped planestwisted relative to the plane of the boss portion 2, and the connectionportions 4 between the blade portions 3 and the ring portion 1 can beformed in one piece such that sloped concave portions 16, depresseddiagonally including the ring portion 1, are flush with the slopedplanes of the blade portions 3.

In this case, it is possible to form the robust connection portionsbetween the blade portions 3 and the ring portion 1, thus providing along-life fan with ring.

Further, the manufacturing method of the present invention has a step ofplastically working the metal plate into a pan shape so as to form thecylindrical ring portion 1 on the periphery and providing the bossportion 2 at the center of the bottom portion and another step offorming the blade portions 3 by cutting out the blade portions radiallyfrom the boss portion 2 and cutting all portions except for theconnection portions 4 between part of the front end edges of the bladeportions 3 along the radius and part of the edge of the ring portion 1,thus allowing manufacture of a fan with ring from a single metal platewithout undue efforts. This provides an inexpensive fan with ring withsmall part count.

In the foregoing manufacturing method, it is possible to conduct plasticworking of the blade portions 3 in which the blade portions 3 aretwisted relative to the boss portion 2. This provides a fan with ringwith a high airflow-generating capability.

To form the plurality of blade portions 3 radially from the boss portion2, the manufacturing method can be provided with a step of cutting thecontours of the blade portions 3 except for both edges along the widthand part of the front end portions of the blade portions 3 and anotherstep of forming enlarged hole portions 13 for crack prevention at thecontour edges of the front end portions of the blade portions 3. Thisprevents cracking at the base portion between the blade portions 3 andthe ring portion 1 during plastic working in which the blade portions 3are twisted relative to the boss portion 2.

The manufacturing method allows, after plastic working of the metalplate into a shallow pan shape, formation of the plurality of slopedconcave portions 16 for formation of sloped surfaces of the bladeportions on the pan bottom outer surface side; the periphery portions ofthe sloped concave portions 16 including their edges and the slopedconcave portions 16 being evenly spaced from one another along thecircumference and being depressed radially from the pan center. In orderfor the front end portions of the blade portions 3 along the radius andpart of the edge of the ring portion 1 to constitute the sloped concaveportions 16 in themselves, these portions can be left uncut as theconnection portions 4. This provides a highly strong, crack-resistantand presentable fan with ring.

The manufacturing method allows advance formation of the enlarged holeportions 13 for crack prevention on both ends of the connection portions4. This provides a further robust fan with ring.

Any of the aforementioned manufacturing methods can be provided with astep of forming, in advance and from the inside of the pan bottom,notches 15 not stretching to the outer surface of the metal plate at theboundary between the pan edge and the ring portion 1 periphery and atthe front end edges of the blade portions, following the step ofplastically working the metal plate into the shallow pan shape. Thisprolongs mold life and ensures accuracy and reliability in formation ofthe fan blade portions.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A, 1B and 1C illustrate explanatory views showing in successionsteps of molding a fan with ring of the present invention from a singlemetal plate;

FIG. 2A illustrates a front view of the fan with ring manufactured bythe manufacturing method of the present invention, and FIG. 2Billustrates a vertical sectional view of the fan with ring manufacturedby the manufacturing method of the present invention;

FIG. 3 illustrates a front view of another embodiment of the fan withring of the present invention;

FIG. 4 illustrates an explanatory perspective view of a cracked portion14 in a connection portion 4 when the embodiment in FIG. 3 is notprovided with enlarged hole portions 13;

FIG. 5 illustrates a perspective view of an intermediate step of anothermanufacturing method of the fan with ring of the present invention;

FIG. 6 illustrates a perspective view of a final step of the same fanwith ring;

FIGS. 7A, 7B, 7C and 7D illustrate preliminary steps of formingcircumferential slits 6 in the fan with ring of the present invention,with FIG. 7A being an overall vertical sectional view, FIG. 7B being anexpanded view of part B in FIG. 7A, FIG. 7C being an expanded sectionalview of a notch 15 formed by the step, and FIG. 7D being an explanatorybottom view of the notches 15; and

FIGS. 8A and 8B respectively illustrate a front view and verticalsectional view of a conventional ring-equipped resin fan 12.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will now be described withreference to the accompanying drawings.

FIGS. 1A to 1C show in succession the manufacturing steps of the fanwith ring of the present invention while FIGS. 2A and 2B illustratefront and vertical sectional views of the fan with ring manufactured bythe manufacturing method of the present invention.

The fan with ring is manufactured by press-molding a thin metal platesuch as aluminum or stainless steel plate. The metal plate is firstdeep-drawn into a shallow pan shape so as to form the cylindrical ringportion 1 on the outer perimeter as shown in FIG. 1A.

Next, the boss portion 2 is formed at the center of the bottom portionof the pan shape, and slightly bending radial slits 5 are blanked atboundaries between the blade portions 3 such that a number of the bladeportions 3 are arranged radially from the boss portion 2 as shown inFIG. 1B.

Next, all portions are cut, except for the connection portions 4 betweenpart of the front end edges of the blade portions 3 along the radius andpart of the edge of the ring portion 1, and the blade portions aresubjected to bending in which the blade portions 3 are twisted in thesame direction relative to the boss portion 2 as shown in FIG. 1C.

Note that the center hole 7 is drilled at the center of the boss portion2 as shown in FIGS. 2A and 2B. Drilling of the center hole 7 can becarried out concurrently with the step shown in FIG. 1B or 1C. Thecenter hole 7 may also be drilled after either of the steps.

The edge portion on the air inlet side of the ring portion 1 is slightlyexpanded, thus forming a bellmouth portion 8 as shown in FIG. 2B. Theblade portions 3 are twisted as shown in FIG. 2B, with part of the backside of each of the blade portions 3 projecting more backward than theback end edge of the ring portion 1.

The fan with ring thus constructed has the front end portion of a motorrotary shaft 10 not shown inserted into the center hole 7 of the bossportion 2 via a spacer 9, with a nut 11 screwed up and tightened on thefront side of the fan with ring.

Next, FIG. 3 shows a second embodiment of the fan of the presentinvention. In this example, the enlarged hole portions 13 are providedon both sides of each of the circumferential slits 6 of the fan shown inFIG. 2A.

The enlarged hole portions 13 are designed to prevent occurrence of acracked portion 14 shown in FIG. 4 at the boundary between thecircumferential slits 6 and the connection portions 4 when theconnection portions 4 formed between both ends of the circumferentialslits 6 undergo plastic deformation in which the connection portions 4are twisted. In the absence of the enlarged hole portions 13, when theplane of the blade portion 3 is sloped by press-molding, twisting occursin the connection portions 4, occasionally resulting in a crack betweenthe connection portions and the circumferential slits 6.

To form the enlarged hole portions 13, it suffices to drill in advancecircular holes spaced from one another at the corresponding positionsand form the circumferential slit 6 between each pair of the circularholes later. Thus, formation of the enlarged hole portions 13 at theends of the circumferential slits 6 prevents cracking to the extentpossible as stress concentration is difficult to take place at theboundary between the circumferential slits 6 and the connection portions4 even when the blade portions 3 are twisted around the connectionportions 4.

Next, FIGS. 5 and 6 illustrate perspective views of a third embodimentof the fan with ring of the present invention. FIGS. 5 and 6 show insuccession the manufacturing steps.

In this example, a metal plate is first press-molded into a pan shapethrough deep drawing as was done in FIG. 1A. Next, the sloped concaveportions 16 are formed equidistantly along the circumference in thesecond deep drawing step as shown in FIG. 5. The sloped concave portions16 are formed radially from the center to the periphery, with the crosssection formed into an odd V shape. The front end portions of the slopedconcave portions 16 are depressed including the periphery of the ringportion 1.

Next, the boss portion 2 is formed at the center of the bottom portionof the pan shape, and the blade portions 3 are slit and formed radiallyfrom the boss portion 2 as shown in FIG. 6. At this time, the front endportion of the blade portion 3 along the radius is cut only where thesloped concave portion 16 does not exist, thus making the sloped concaveportion 16 in itself part of the blade surface of the blade portion 3.The sloped concave portion 16 in itself is the sloped surface of theblade portion 3 formed in advance for the boss portion 2. Only bothsides of the blade portion 3 extending along the radius and part of itsfront end are slit and formed. Note that all the remaining slopedconcave portion 16, except for the portion that will be the bladeportion 3, is cut off in slit form. This perfectly prevents occurrenceof the cracked portion 14 described with reference to FIG. 4.

FIGS. 7A, 7B, 7C and 7D illustrate working means for forming therespective circumferential slits 6 shown in FIGS. 1 to 3 and FIG. 6.

As an example, the boundary portions between the ring portion 1 of themetal plate formed into a shallow pan shape and the pan bottom arenotched at even spacings from the inner surface side of the pan to formthe notches 15 as shown in FIGS. 7A, 7B, 7C and 7D at thecircumferential slit 6 positions shown in FIG. 1A. The notches 15 notstretching to the outer surface of a pan-shaped metal plate 19 areformed by notching the pan-shaped metal plate 19 using an edge portion20 projected intermittently on the periphery of a lower mold 17. This isdesigned to prevent excessive wear of molds used to form thecircumferential slits 6 shown in FIG. 2.

It should be borne in mind that while a crack may occur that stretchesfrom the notch 15 to the outer surface of the pan-shaped metal plate 19after formation of the notches 15, this does not present any practicalproblems because this portion will be later slit and formed.

Then, the radial slits 5 are formed and blanked. The blade portions areplastically deformed so as to be twisted by other press mold. Thisallows the front edge of the blade surface, except for part of the edge,to be cut and the blade surface to be twisted and sloped relative to theboss portion because of existence of the notch 15.

Note that when the notches are formed, the pan-shaped metal plate 19 isclamped between an upper mold 18 and the lower mold 17 and part of thepan-shaped metal plate 19 is notched by the edge portion 20.

Thus, provision of the notches 15 in advance ensures easy formation ofthe circumferential slits 6 and long life of the edge portion 20 of thelower mold 17.

1. A fan with ring comprising: a cylindrical ring portion having agenerally cylindrical outer face, said cylindrical outer face having afirst end and a second end; and a plurality of blade portions locatedwithin the ring portion and projected radially from a boss portion,wherein the fan with ring comprises connection portions constituted byconnecting in one piece part of a front end edge of each of the bladeportions with part of an edge of the ring portion, the blade portions,the ring portion, and the boss portion are molded in one piece from apress-molded form of a single metal plate, a blade surface of each ofthe blade portions has a sloped plane twisted relative to a plane of theboss portion, the connection portions at the front ends of the bladeportions are formed in one piece such that sloped concave portions, thatare diagonally depressed, with edges included in the ring portion, areflush with the sloped planes, said first end of said cylindrical outerface comprises outer peripheral arcuate segments, said edges of saidsloped concave portions which are included in the ring portion arecontinuous with said arcuate segments, said edges of said sloped concaveportions extending away from said first end of said cylindrical outerface towards said second end of said cylindrical outer face, said edgesof said sloped concave portions converging from respective said arcuatesegments towards said second end of said cylindrical outer face.
 2. Amethod of manufacturing a fan with ring comprising: plastically workinga metal plate into a shallow pan shape so as to form a cylindrical ringportion on a periphery of said pan shape; forming notches inside of thepan bottom at positions corresponding to front end edges of bladeportions at a boundary between a bottom edge of the pan and theperiphery of the ring portion of the pan, the notches not stretching toan outer surface of the metal plate; forming a boss portion at a centerof a bottom portion of the pan shape; slitting and forming bladeportions radially from the boss portion; and cutting around blade andring portions except for part of a front end edge of each of the bladeportions, part of the edge of the ring portion for use as connectionportions, and a part connecting the blade portions with the bossportion.
 3. A fan with ring produced according to the method of claim 2.4. A method of manufacturing a fan with ring comprising: plasticallyworking a metal plate into a shallow pan shape so as to form acylindrical ring portion on a periphery of said pan shape; formingnotches inside of a pan bottom at positions corresponding to front endedges of blade portions at a boundary between a bottom edge of the panand the periphery of the ring portion of the pan, the notches notstretching to an outer surface of the metal plate; forming a bossportion at a center of a bottom portion of the pan shape; cutting atleast contours of both edges along sides of each of blade portions inorder to form a plurality of blade portions radially from the bossportion; cutting around blade and ring portions, except for part of afront end edge of each of the blade portions, part of the edge of thering portion for use as connection portions, and a part connecting theblade portions with the boss portion; and twisting each of the bladeportions relative to the boss portion.
 5. A method of manufacturing afan with ring comprising: plastically working a metal plate into ashallow pan shape so as to form a cylindrical ring portion on aperiphery of said pan shape; forming notches inside of a pan bottom atpositions corresponding to front end edges of blade portions at aboundary between a bottom edge of the pan and the periphery of the ringportion of the pan, the notches not stretching to an outer surface ofthe metal plate; forming a boss portion at a center of a bottom portionof the pan shape; cutting all contours of a plurality of blade portionsexcept for both edges along a width of each blade portion and part of afront end portion of each of the blade portions in order to form aplurality of blade portions radially from the boss portion; formingenlarged hole portions at edges of the front end portions adjacent toconnecting portions; cutting around the blade and ring portions, exceptfor part of a front end edge of each of the blade portions, part of theedge of the ring portion for use as connection portions, and a partconnecting the blade portions with the boss portion; and twisting eachof the blade portions relative to the boss portion.
 6. A method ofmanufacturing a fan with ring comprising: plastically working a metalplate into a shallow pan shape so as to form a cylindrical ring portionon a periphery, said ring portion having a generally cylindrical outerface, said cylindrical outer face having a first end and a second end;forming a plurality of sloped concave portions for formation of bladeportion sloped surfaces on an outer side of a pan bottom, the slopedconcave portions being evenly spaced apart from one another along acircumference and being depressed radially from a center of a panbottom, with edges of the sloped concave portions included inperipheries of the pan shape, said first end of said cylindrical outerface comprising outer peripheral arcuate segments and edges of saidsloped concave portions being continuous with said arcuate segments,wherein said edges of said sloped concave portions extend away from saidfirst end of said cylindrical outer face towards said second end of saidcylindrical outer face, said edges of said sloped concave portionsconverging from respective said arcuate segments towards said second endof said cylindrical outer face; forming the boss portion at a center ofa bottom portion of the pan shape; slitting and forming blade portionsradially from the boss portion such that the sloped concave portionsconstitute part of the respective blade portions; and cutting around theblade and sloped concave portions, except for a part connecting theblade portions with the boss portion, and a boundary between at least afront edge portion of each of the blade portions and the ring portionfor use as a connection portion, such that the boundary constitutes thesloped concave portion itself.
 7. A method of manufacturing a fan withring comprising: plastically working a metal plate into a shallow panshape so as to form a cylindrical ring portion on a periphery; forming aplurality of sloped concave portions for formation of blade portionsloped surfaces on an outer side of a an bottom, the sloped concaveportions being evenly spaced apart from one another along acircumference and being depressed radially from a center of a panbottom, with edges of the sloped concave portions included inperipheries of the pan shape; forming the boss portion at a center of abottom portion of the pan shape; slitting and forming blade portionsradially from the boss portion such that the sloped concave portionsconstitute part of the respective blade portions; cutting around theblade and sloped concave portions, except for a part connecting theblade portions with the boss portion, and a boundary between at least afront edge portion of each of the blade portions and the ring portionfor use as a connection portion, such that the boundary constitutes thesloped concave portion itself; and forming notches inside of the panbottom at positions corresponding to front end edges of blade portionsat a boundary between a bottom edge of the pan and the periphery of thering portion of the pan, the notches not extending to an outer surfaceof the metal plate.
 8. A fan with ring comprising: a cylindrical ringportion; and a plurality of blade portions located within the ringportion and projected radially from a boss portion, wherein the fan withring comprises connection portions constituted by connecting in onepiece part of a front end edge of each of the blade portions with partof an edge of the ring portion, the blade portions, the ring portion,and the boss portion are molded in one piece from a press-molded form ofa single metal plate, a blade surface of each of the blade portions hasa sloped plane twisted relative to a plane of the boss portion, theconnection portions at the front ends of the blade portions are formedin one piece such that sloped concave portions, that are diagonallydepressed, with edges included in the ring portion, are flush with thesloped planes, and said sloped concave portions extend to a portion ofan outer side of said ring portion, and concave surfaces of said slopedconcave portions face away from said ring portion.
 9. A method ofmanufacturing a fan with ring comprising: plastically working a metalplate into a shallow pan shave so as to form a cylindrical ring portionon a periphery; forming a plurality of sloped concave portions forformation of blade portion sloped surfaces on an outer side of a anbottom, the sloped concave portions being evenly spaced apart from oneanother along a circumference and being depressed radially from a centerof a pan bottom, with edges of the sloped concave portions included inperipheries of the pan shape; forming the boss portion at a center of abottom portion of the pan shape; slitting and forming blade portionsradially from the boss portion such that the sloped concave portionsconstitute part of the respective blade portion; and cutting around theblade and slaved concave portions, except for a part connecting theblade portions with the boss portion, and a boundary between at least afront edge portion of each of the blade portions and the ring portionfor use as a connection portion, such that the boundary constitutes thesloped concave portion itself, wherein said sloped concave portionsextend to a portion of an outer side of said ring portion, and concavesurfaces of said sloped concave portions face away from said ringportion.